Ammonium salt



Reissued July 29, 1930 UNITED STATES PATENT OFFICE EDWARD WDLLIAM HARVEY, OF NEW BRUNSWICK, NEW JERSEY, ASSIGNOR TO THE BARRETT COMPANY, A CORPORATION OF NEW JERSEY AMMONIUM SALT 1T0 Drawing. Original application filed August 16, 1922, Serial No. 582,134. Renewed October 5, 1925. Original No. 1,608,737, dated November 30, 1926. Application for reissue filed November 80, 1928.

Serial N0. 322,958.

My invention relates to drying and improving the physical condition of ammonium salts by lowering the percentage of free acid and free moisture contained therein.

In the production of ammonium sulfate by the usual processes, as for example as a byproduct from illuminating gas manufacture and coke works, or when ammonia has been obtained directly from the air synthetically, it has been customary to pass the gases containing ammonia through a saturator bath of sulfuric acid solution whereupon the ammonium sulfate is formed and is precipitated when the concentration reaches the proper amount. These crystals are collected and the surplus liquor is drained off or removed in the centrifugal. Some of the acid mother liquor clings to the surfaces of the crystals. The bulk of the moisture can be removed without great dilficulty, but even a very small residue of the same is objectionable. The removal of these last small amounts of acid and water is very difl lcult. Ammonium sulfate in such a condition, containing some free acid and free moisture, is difficult to handle, ship and use because of its poor physical condition and the tendency of the free acid to retain and absorb moisture and to destroy the fiber of the bags in which it may be contained.

By my invention much or all of the free acid of the ammonium sulfate is neutralized, or a sulfate is formed therefrom, and much or all of the free moisture of the ammonium sulfate is chan ed from the free state to a chemically combined state by the addition of one or morematerials for this purpose. It is preferable to add a material which is itself a fertilizer and which will at the same time overcome the deleterious properties of the impure ammonium sulfate.

In practicing this invention I may add to the ammonium sulfate as usually prepared a mixture of hemi-hydrate of calcium sulfate (CaSOJ H O, calcium oxide (CaO) calcium hydroxide [Ca(OH) and calcium carbonate (CaCO,), or I may add hemi-hydrate of calcium sulfate alone in suitable proportion, or I may add any suitable commen cial product containing among its several ingredients hemi-hydrate of calcium sulfate and a basic material or materials, as calcium oxide or calcium hydroxide, such a commercial product being commonly known as stucco or plaster of Paris. All of the above materials used as additions are to be added in a finely divided or powdered state. The action of such additions to ammonium sulfate has the following efi'ect.

First, the bases neutralize the free acid and absorb some moisture, according to the formula Ca 011 +n,.so,= oaso..2H.o C3003 l O GaSO4-2H2O 002 Second, the hemi-hydrate of calcium sulfate (CaSO .H O dries the mixture by combining with the free moisture contained in the mixture, in accordance with the following formula- (021800 11 0 2 (CaSO-2Hg0 The relative proportion of base to hemi-hydrate of calcium sulfate and the amount of such mixture necessary to dry it given amount of ammonium sulfate will depend upon the amount of free acid and free moisture in the ammonium sulfate to be so dried and neutralized, and said roportions and amounts can be determined y chemical analysis and formula.

The amounts of hemi-hydrate of calcium sulfate or of said mixture of hemi-hydrate and basic material used should not be large enough to cause decomposition of an appreciable amount of ammonium sulfate with consequent loss of ammonia. The amount of said admixture may vary from a fraction of 1 per cent to 10 per cent of the ammonium sulfate to be treated, depending upon the amount of free sulfuric acid and free water in the ammonium sulfate.

Ammonium sulfate treated as above described has been found to be greatly benefited as to physical condition after such treatment and is much more satisfactory. The ammonium sulfate may be mixed with the fine- 1y divided material in any convenient way or the material may be blown or otherwise applied as a dust over the ammonium sulfate crystals, as the crystals are agitated or the *mass is olled, or the mixture of the ammonium sulfate and the material to be added ma be effected in any other convenient wa he terms commercial ammonium su fate or commercial ammonium salts as used in the claims are intended to include ammonium salts, the moist condition or water content of which corresponds to that of ammonium salts which have been dried in accordance with usual practice and contain only the residual moisture not removed by the usual drying operations.

While the invention has been specifically described in connection with ammonium sulfate, it is also applicable to the treatment of ammonium chloride for the pur ose of improving its phgsical condition an producing a more desira le product.

I claim:

1. The process of improving the condition of commercial ammonium sulfate, which comprises adding thereto a mixture comprising a material containin a basic calcium compound, and hemi-h rate of calcium sulfate.

2. The process 0 improving the condition of commercial ammonium sulfate, which comprises adding plaster of Paris thereto.

3. The process of improving the condition of commercial ammonium sulfate, which comprises adding thereto less than 10% of a mixture containing finely divided basic material and hemi-hydrate of calcium sulfate.

4. The process of improving the condition of commercial ammonium sulfate, which comprises adding thereto a mixture containing hemi-hydrate of calcium sulfate and a basic material in amount insuflicient to decompose an appreciable quantity of the ammonium sulfate.

5. The process of drying and improving the hysical condition of commercial ammomum sulfate which comprises adding thereto less than 10% of a material containing powdered plaster of Paris.

6. The process of drying, neutralizing and improving the physical condition of commercial ammonium sulfate which comprises adding thereto a material containing powdered 'hemihydrate of calcium sulfate and basic material.

7 The process set forth in claim 5, in which the material is added to the ammonium sulfate by blowing it thereon.

8. The process set forth in claim 6, in which the material is added to the ammonium sulfate by blowing it thereon.

9. The process of improving the condition of inorganic commercial ammonium salts adapted to be used as fertilizers, which involves only the addition thereto of a small amount of hemi-hydrate of calcium sulfate to remove the residual moisture remaining in said salts.

10. The process of improving the condition of inorganic commercial ammonium salts adapted to be used as fertilizers. which involves only the addition thereto of a small amount of basic material mixed with hemihydrate of calcium sulfate.

11. The process of improving the condition of inorganic commercial ammonium salts which com rises adding thereto a small amount of emi-hydrate of calcium sulfate and avoiding the introduction of moisture into the mass to remove the residual moisture remaining in said salts.

12. The process of improving the condition of a mass of commercial ammonium sulfate, which com rises adding thereto a small amount of emi-hydrate of calcium sulfate to remove the residual moisture remaining in said mass of ammonium sulfate while avoiding the introduction of moisture into said mass to remove the residual moisture remainin in said salts.

n testimony whereof, I hereto aflix my signature.

EDWARD WILLIAM HARVEY.

CERTIFICATE OF CORRECTION.

Reissue Patent No. 17,756. Granted July 29, 1930, to

EDWARD WILLIAM HARVEY.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, lines 88 and 89,

claim 12, strike out the words "to remove the residual moisture remaining insaid salts"; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 9th day of September, A. D. 1930.

M. J. Moore, (Seal) Acting Commissioner of Patents. 

